I. Field of the Invention
The current invention relates to mobility within a telecommunications system. More particularly, the present invention relates to a method and apparatus for transparently relocating an anchor point within the serving network of a wireless telecommunications system from one location to another.
II. Description of the Related Art
The use of a decentralized serving network for use in a wireless telecommunications system is disclosed in U.S. Pat. No. 6,215,779, entitled “DISTRIBUTED INFRASTRUCTURE FOR WIRELESS DATA COMMUNICATIONS”, applied for by the applicant of the present invention, and incorporated by reference herein. The above application discusses a telecommunications decentralized serving network in which, rather than there being a single point of control, there are multiple control points distributed throughout the serving network of the telecommunications system.
The Internet Engineering Task Force (IETF) is the standards body that creates the majority of standards related to the Internet Protocol (IP). Many of the standards created by the IETF are called RFCs. RFC is shorthand for ‘Request For Comments.’
Open Shortest Path First (OSPF) was standardized by the IETF to address, in part, the routing of packets in a network in which one or more of the routers experiences a failure, thus enhancing the reliability of a network. OSPF was designed in such a way that, of all the routers which are working at any given moment, the shortest path is taken from node A to node B. Additionally, OSPF was designed such that, if multiple equivalent routes exist from node A to node B, any one of the equivalent routes can be selected. With OSPF in place, a network with redundant routes can perform load balancing on the routers. OSPF is available on many makes and models of routers, and is described in IETF RFC 2328, incorporated by reference herein.
Mobile IP is present in many IETF standards to make it possible for a device, containing an IP address, to travel through a network (or networks). The standard, RFC 2002, ‘IP Mobility Support,’ incorporated by reference herein, addresses the problem of IP Mobility, and uses a solution termed ‘Mobile IP.’ Several other Mobile IP related standards also exist, such as RFCs 2006, 2041, 2290, 2344, and 2356, each of which is incorporated by reference herein. Local Area Network (LAN) system administrators that want to support mobility are guided by the IETF standards to use Mobile IP. Mobile IP provides support not only for mobility within a LAN, but also for mobility within a Wide Area Network (WAN).
In a decentralized telecommunications network, the service devices chosen are widely available off-the-shelf units that use open standards for their interfaces rather than proprietary protocols that are limited to a single supplier. Many, if not all, of the service devices are designed to communicate with a single anchor point for each active session. Meaning, such off-the-shelf devices, and the protocols they incorporate, are not designed to begin a session with one device and ends the same session with a different device. This restriction can lead to non-optimized routing for individual sessions. Such non-optimized routing situations are illustrated in FIG. 8A and FIG. 8B. What is needed is a method by which a service device's anchor point for an active session can be relocated without the need for specific anchor point relocation support in the service device. Specifically, such a method should be very efficient and robust, minimizing latency and bandwidth usage.